- Synthesis of 4-acetylbenzoxazolin-2(3H)-one reported from Zea mays
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A three-step alternative synthesis of 4-acetylbenzoxazolin-2(3H)-one (4) is reported. Starting from inexpensive 3-hydroxyacetophenone (1) 3-hydroxy- 2-nitroacetophenone (2) is prepared by nitration followed by catalytic hydrogenation to yield 2-amino-3-hydroxyacetophenone (3) in which a C=O unit is inserted by means of bis(trichloromethyl)carbonate (triphosgene) in the presence of triethylamine to afford 4 in 35% overall yield.
- Kluge,Sicker
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- One-pot oxidative hydrolysis-oxidative cleavage of 7-borylindoles enables access to: O -amidophenols and 4-acylbenzoxazoles
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7-Borylindoles undergo a one-pot oxidative-hydrolysis of the arylboronate and oxidative cleavage of the indole C2-C3 double bond to afford o-amidophenol derivatives. Subsequent cyclisation delivers benzoxazoles bearing an acyl group at C4, a substitution pattern common to fungal-derived benzoxazole alkaloids. Using 7-borylindoles as substrates to access functionalised o-amidophenols circumvents the difficult preparation of these compounds from arenes, streamlining access to substituted 4-acylbenzoxazoles in the process.
- Anderson, Kirsty,Eastabrook, Andrew S.,Sperry, Jonathan
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p. 3559 - 3562
(2020/04/09)
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- Topoisomerase I-mediated antiproliferative activity of 10-substituted and 12-substituted homocamptothecins
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Homocamptothecin (hCPT) is an E-ring modified camptothecin (CPT) analogue, which showed pronounced inhibitory activity of topoisomerase I. In search of novel hCPT-type anticancer agents, two series of hCPT derivatives were synthesized and evaluated in vitro against three human tumor cell lines. The results indicated that the 10-substituted hCPT derivatives had a considerably higher cytotoxic activity than the 12-substituted ones. Among the 10-substituted compounds, 8a, 8b, 9b, and 9i showed an equivalent or even more potent activity than the positive control drug topotecan against the lung cancer cell line A-549. Moreover, the hCPT analogues 8a and 8b exhibited a higher topoisomerase I inhibitory activity than CPT at a concentration of 100 μM. Copyright
- Guo, Wei,Liu, Wenfeng,Zhu, Lingjian,Zhang, Yongqiang,Cheng, Pengfei,Dong, Guoqiang,Zhuang, Chunlin,Yao, Jianzhong,Sheng, Chunquan,Miao, Zhenyuan,Zhang, Wannian
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experimental part
p. 1539 - 1549
(2011/11/05)
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- Biomimetic Synthesis of 4-Acetylbenzoxazolin-2(3H)-one Isolated from Zea mays
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4-Acctylbenzoxazolin-2(3H)-one has been prepared biomimetically during attempts to synthesize the hemiacetalic hydroxamic acid 5-acetyl-2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one by the immediate degradation of this unstable compound generated as an intermediate. Thus, 4-acetylbenzoxazolin-2(3H)one recently isolated from Zea mays kernels, and similar to other benzoxazolin-2(3H)-ones known from plant sources, is assumed to have originated from the degradation of natural 5-acetyl-2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one which in turn could have been enzymatically released by a β-glucosidase from the corresponding 2-β-D-glucoside.
- Escobar, Carlos A.,Kluge, Michael,Sicker, Dieter
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p. 1407 - 1414
(2007/10/03)
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